1. Technical Field
The present disclosure relates to a magnetic relay device made using MEMS (microelectromechanical systems) or NEMS (nanoelectricalmechanical systems) technology.
2. Detailed Description
As is known, relays are traditionally used as switches in power circuits, for example for controlling actuators and DC electric motors, due to their capacity for carrying and interrupting high electric currents.
For example, relays are used in applications requiring a very high resistance in an open condition (e.g., a resistance of the order of megaohms) and a very low resistance in the closed condition (e.g., a resistance of tens of microohms).
Traditional relays, such as reed relays and the like, are, however, very cumbersome, to the point of being at times much bulkier than the devices to be controlled.
This dimension relationship is becoming increasingly more evident, given the trend towards miniaturization of control and driving devices and, at times, of the utilizers.
In the last few years, integrated relays have thus been proposed that have dimensions comparable to those of integrated circuits and may be directly connected to logic devices. For example, U.S. Pat. No. 6,320,145 discloses a magnetostatic relay or switch obtained using the MEMS manufacturing technique and having a beam extending as a cantilever above a substrate. The beam, of conductive material and provided with a magnetic material layer, such as permalloy, or made directly of magnetic material, is mobile under the influence of a magnetic field generated on an opposite side of the substrate so as to touch, or move away from, a contact formed on the substrate, thus closing and opening a circuit.
Even though this solution enables a reduction in dimensions, it may be improved. In fact, the distance between the magnetic-field generator and the contact structure does not ensure proper operation of the relay, unless strong magnetic fields are used, which may prove disadvantageous or impossible in certain applications. In addition, upon opening of the contact, sparks are created that deteriorate the material, reducing the service life of the relay. In addition, with use, the beam tends to undergo deformation, also on account of the existing electrostatic forces, rendering more difficult proper contact and/or separation during switching.